The present invention relates to a perforating jig for perforating cards or sheets of paper for insertion into loose-leaf notebooks or ring binders.
Loose-leaf notebooks or ring binders are designed to carry leaves of paper prepared for use therein. Account books of the loose-leaf type have a similar design. Heretofore, one who has a loose-leaf notebook is required to purchase commercially available spare sheets of paper which have already been perforated to suit that particular loose-leaf notebook. However, there has recently been a trend among students, researchers and others to use large-sized cards, usually about 128.times.182 mm in size, instead of conventional notebooks or for maintaining information collected on paper. Perforated cards of that size (having perforations at 8 cm intervals) have been on the market. Relatively thick unperforated cards have also been offered for sale, which purchasers oftentimes find it necessary to put in a loose-leaf notebook or ring binder.
Unperforated cards or sheets of paper can be perforated by being folded into a two-ply structure and then by being pierced on a punch with the center of the folded sheet being aligned with a central positioning mark on the punch. Relatively thick cards or sheets cannot be folded neatly with ease, and to fold such thick cards or sheets is not desirable. It is tedious and time-consuming to perforate such thick cards or sheets when only a one-hole perforating punch is at hand.
U.S. Pat. No. 3,172,325 discloses one known device for making a plurality of holes through unperforated cards or sheets for insertion in ring binders. The disclosed perforating device comprises upper and lower metal plates coupled with each other by a hinge, the lower metal plate having one or more punch projections and the upper metal plate having corresponding openings for mating with the punch projections. When in use, a sheet or card to be perforated is inserted between the upper and lower metal plates, and the upper metal plate is moved toward the lower metal plate. As the punch projections on the lower metal plate pass into the openings in the upper metal plate, the sheet will be perforated.
With the prior perforating device, a large amount of force would have to be exerted to push the upper metal plate down toward the lower metal plate when perforating a thick card or sheet of paper, so that the perforating task has been quite laborious.